Michael T Pugh

US Patent:

45845379, Apr 22, 1986

Filed:

Apr 17, 1985

Appl. No.:

6/724248

Inventors:

Michael W. Pugh - Oceanside CA

Assignee:

Burroughs Corporation - Detroit MI

International Classification:

H03L 706

US Classification:

331 1A

Abstract:

An all digital circuit which operates with an electronic oscillator of the type that receives an input signal and synchronizes its oscillations to transitions in the input signal, comprises: a pulse-generating circuit 20 coupled to the oscillator for digitally forming periodic pulses in synchronization with selected oscillations of the oscillator; a detecting circuit 30 coupled to receive the pulses and the input signal for digitally detecting whether a transition occurs in the input signal in the absence of a pulse; and a counting circuit 40 coupled to the detecting circuit for digitally counting so long as the detecting circuit fails to detect a transition in the absence of a pulse and for indicating the oscillator is synchronized when the count reaches a predetermined number.